00:01
In this problem, we want to note the major structural differences are between starch and cellulose.
00:06
In order to understand the structural differences between these two chemical structures, we first need to understand the difference between alpha and beta isomers of glucose monomers.
00:17
Shown on the left is the alpha glucose monomer in which this hydroxy group, which is located on this first carbon, is in the down position, meaning it's below the ring.
00:28
In contrast, the beta glucose monomer has that same hydroxy group in the up position, again, on that first carbon.
00:37
Everything else between these two monomers is identical, so that's what distinguishes them from each other.
00:43
Now, if we look at the structure of starch, we see that it has one -four linkage between those two glucose monomers, and this hydroxy group, which bonded with the other monomer, is in the down position.
00:59
And this structure continues as the monomers continue to build.
01:04
So starch is defined by that alpha linkage since that hydroxy group is in the down position...